Two hundred celebrities, politicians, business leaders and more have signed a letter calling for equality between physical and mental health in advance of the government spending round.

The new campaign is being led by Norman Lamb, the Liberal Democrat former health minister; Alastair Campbell, the former Downing Street director of communications; and Andrew Mitchell, the former Tory Cabinet minister. Each has faced mental health problems himself or in his family.

It calls on the government to address the historic inequality between mental and physical health, highlighting lack of access to treatment, lengthy waiting times, inadequate crisis care, use of police cells and the 20 year gap in life expectancy between those with mental health problems and the rest of the population.

The signatories say:

“We ask for the same right to timely access to evidence-based treatment as is enjoyed by those with physical health problems. We accept, and urge ministers to accept, that this will require additional investment in mental health services. Ministers have accepted that whatever improvements in attitude may have been made in British society, those who experience mental ill-health still do not get a fair deal from our health services. In effect they suffer discrimination in our publicly-funded NHS. This must be addressed.”